People like to opine on things that they don’t know much about and I’m as guilty as the next person, but I actually do know something about viruses (MD/PhD in neonatology and virology) so I figured I’d put something out there about COVID-19 and my experience in virology in general. I’ll start with the most important thing. Wash your hands and don’t touch your face! That’s how it gets in. More on that later.
Virology geek-out
First of all, it’s important that you understand the difference between viruses and bacteria. Bacteria, in general, are independently living organisms that can reproduce without our help and are large enough to see under a regular microscope. Most of them are harmless and we have millions of them living in our bodies. If they do cause an infection, most cases can be treated with antibiotics. We also have vaccines against some of the more serious bacterial infections such as Pertussis (Whooping Cough) and Pneumococcus (Pneumonia, Ear Infections). Viruses, on the other hand are much smaller and can’t reproduce on their own. They need a host in order to spread. There are some anti-viral medications, especially for HIV/AIDS and Herpes Virus, but for the most part we don’t have much to treat them directly and have to let infections run their course. We have excellent vaccines for many of the major ones and because of that we hardly ever see them in clinical practice.
When I was a graduate student in virology, we used to talk about virus design. Not in terms of making our own but rather appreciating the clever ways viruses mutate, propagate and cause disease. The way we saw it, each virus had its own superpower. The thing that kept it in circulation.
For example, Measles spreads easily through the air. No need to touch anything. You just breathe it in. That’s not true almost of any other virus (Tuberculosis, a bacterium, does it too). Herpes viruses, which include chicken pox, has the ability to stay in your body for life and come back from time to time (cold sores, shingles etc.). Thankfully we have a very effective vaccine for it which depends on nearly everyone getting vaccinated to prevent spread of the disease.
Influenza, known as “the flu” has a genome with 8 chromosomes. Aside from mutating to evolve, it can also re-assort those chromosomes like a hand of cards in poker. When someone (or an animal) is infected with two different flu strains, they can produce a new virus what’s a hybrid of the two and sometimes one what’s much more pathogenic and one the world has never seen before. It’s also why the flu vaccine is so hard to get right each year. They have to guess in the spring which flu virus strains are going to circulate to make the vaccine for the next fall. The 1918 worldwide flu pandemic which killed 50 million people was so deadly because the virus that year had not been previously seen, so nobody was immune and also because it had a much higher case-fatality rate (percent of infected people who die from the infection) than the regular flu which is about 0.05-0.1% in most years. The 1918 flu also had a high case-fatality rate among young people which was unusual. It also didn’t help that World War 1 had soldiers traveling all over the world spreading it.
HIV which was new at the time I was in training is the masterpiece of viral design. It’s very hard to spread but it has multiple superpowers. For one, it is asymptomatic for a long time allowing lots of time to spread. It actually integrates into your DNA so once infected you are (almost) never free of it. It infects immune cells so it hits the cells that are supposed to fight it – which makes vaccine development almost impossible. It is very sloppy at reproducing itself and lots of mutations means it evolves very quickly when faced with a new antiviral drug.
One more example, Ebola, is actually a poorly designed virus. Its superpower is its lethality but that’s actually a weakness because when it kills quickly, that slows the spread. It’s also not terribly contagious.
COVID-19
Now lets talk about the new Coronavirus (COVID-19). It belongs to a family of viruses that are found in both animals and humans. There are several human coronaviruses that don’t cause severe disease, just a routine common cold, and there are two recent ones that are more serious, SARS and MERS. Fortunately, those two aren’t all that contagious, so we were able to contain them by isolating patients.
COVID-19 is most closely related to a bat coronavirus and probably made the jump to humans in China. We have its RNA sequence and that’s how we can put it into the Coronavirus family tree. For all the conspiracy theorists out there, the RNA sequence tells us that it was NOT created in a lab and simply evolved like viruses and all living organisms do.
We know that it started in the Wuhan, China area but there are now cases in many countries around the world, so clearly the virus has not been contained. We have found that this virus is very contagious (that’s it’s “superpower” in my opinion), at least twice that of the flu and more importantly there is no “herd immunity” because we haven’t seen it before. Herd immunity is the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, whether through vaccination or previous exposure.
The good news is that it seems like most people only get a mild illness and some people may not even get sick from it at all. That creates a problem, however. If you’re not sick you will not know to take precautions to spread it to others and it certainly looks like that is happening. It also appears to live on hard surfaces for quite a while so it may become difficult to trace the spread. Keep in mind that your cellphone is a hard surface. It does not appear to have airborne spread but certainly droplets that spray out of your mouth and nose when you cough or sneeze, as far as 6 feet away, can be infectious. If the droplets get in your mouth, nose or eyes you can get infected. If they land on a hard surface and you touch that surface and then touch your mouth, nose or eyes you can also get infected. A surgical mask can help you prevent infecting others if you are sick but it does very little to protect you from getting infected. The best thing you can do is wash your hands and not touch your face. Alcohol based gels also work if you don’t have access to hand-washing.
We still don’t know what the actual case-fatality rate of the virus is and that’s something we’ll only know over time, and it will also change depending on how good we are at treating the most ill patients. The Chinese data, which is very questionable, says about 2% died of the illness, which is about 10-20x higher than the flu (0.05-0.1% case-fatality rate), but we can be fairly certain that’s an overestimate because they are probably not counting all of the people with mild illness. In other countries where outbreaks have occurred it looks like the rate is lower than 1% but again, it’s an evolving situation.
Something else important to know, based on the Chinese data, is that it has a different age distribution for fatalities than the flu. For one, children and young adults are doing quite well. They seem to be resistant to the worst manifestations of the disease in most cases. However, the fatality rate rises in middle age and peaks in the oldest patients. The flu, for comparison, rarely kills middle-aged people. See the graph below.
Controlling the spread of COVID-19 is going to take a coordinated effort among governmental public health agencies as well as each person taking precautions including good hand washing and not touching your face (yes, I’ll keep saying this). The CDC and WHO and say we need to expect that there will be further outbreaks around the country and around the world. How widespread they will be is certainly still uncertain.
In my opinion the key to getting through the Coronavirus outbreak, if we have one, is spreading the cases out over time. The lesson from Wuhan, China was that officials suppressed news of the cases and many more became infected at once before they took action, overwhelming their healthcare system. I see it happening in Iran too. If we get a bunch of cases here in the U.S. at once because we’ve ignored the problem and haven’t taken precautions, our hospitals will be overwhelmed and care will be poor. We may also see shortages of medical equipment and medications which often come from Asia. If we take reasonable measures now to slow the spread, the cases will not all come at once and our healthcare system should be able to handle it, and in a year or so we may have a vaccine. I wouldn’t panic at this point but I am very concerned that it will get worse before it gets better and there’s no harm in being prepared, both physically and mentally. There’s a great Vox article on the topic which I’ve linked here.
I worry that our current presidential administration is making some of the same mistakes as China: calling the virus a “hoax”, suppressing information that gets out to the public, and failing to provide support to local health departments. Call your legislators and make sure they know you want full funding of the response to this virus and full funding of the CDC which has been gutted. They also need to know that any vaccine has to be made available to everyone for it to work. We need to combat this with science, not politics.
Now go wash your damn hands!!!
